The present invention relates to the preparation and administration of a product and, more particularly, to the injection of the same into a living organism, for example, a human body.
Previously, various devices have been developed for the percutaneous delivery of medications into living organisms including syringes in which a liquid is delivered from a chamber using pressure asserted by a manual plunger through a needle inserted under the skin.
Additionally, it is well known in the art that the storage life of certain injectable substances such as glucagon, used to dissolve blood clots, is increased when the substance is stored in a powdered or lyophilized state, for example. These lyophilized substances (i.e., drugs or compounds) are presently used for injection of materials that would otherwise be unstable. Lyophilization, for example, is the rapid freezing of a material at a very low temperature followed by rapid dehydration by sublimation in a high vacuum. The resulting lyophilized compound is typically stored in a glass vial or cartridge which is closed by a cap, such as a rubber stopper or septum.
It is necessary to reconstitute the powdered or solid material, such as a lyophilized compound, prior to administration. This is accomplished by mixing the solid compound with a suitable diluent or liquid. Reconstitution typically involves the use of a syringe with a needle to withdraw the diluent from a separate vial and inject it into the vial containing the compound. The compound is then thoroughly mixed, typically by shaking the vial by hand, and a separate syringe with a needle withdraws the desired amount to be injected into the patient. Because two separate containers are used, the person reconstituting the compound must be certain to mix the correct amounts such that a proper concentration of the mixture results. When a syringe is used to mix the diluent and drug, the exact volume of diluent to drug ratio is difficult to obtain. Thus, precise concentration levels of administered drug may be compromised.
Moreover, because the diluent and compound are in separate, sterilized containers, the manual withdrawal of diluent via a syringe and reinjection of the same into the container containing the solid material such as a powdered or lyophilized drug may compromise sterility, and safety due to the use of a syringe.
Because of increased use of powdered compounds or lyophilized drugs, for example, it is desirable to provide both professional and non-professional personnel with a reconstituted drug delivery system. It is desirable to have a simple, reliable system that facilitates preparation and safe delivery of an accurate dosage of a reconstituted compound. In addition, it is desirable to provide a system that reconstitutes a lyophilized drug while maintaining sterility throughout the process. Also, it is desirable to provide improvements in the percutaneous delivery of medication generally, which provide for safe, effective administration by the user.
The present invention relates to systems and methods for delivering liquid drugs to a user. The drug delivery system can include delivery of reconstituted powdered drugs such as, for example, lyophilized drugs, or more generally for the transfer and delivery of liquid drugs. Powdered or lyophilized drug delivery further includes a system to reconstitute the powdered drug. The drug delivery systems may further include a pressurization system which pressurizes the drug for transfer to a delivery system or for direct subcutaneous delivery. Further, the drug delivery system in accordance with the present invention includes an injector system which contacts the tissue and delivers the drug to the patient or user. In the alternative, the drug delivery system in accordance with the present invention includes filling of detachable delivery devices, for example, a standard syringe, a needleless injector, an infusion device or different types of pumps. Another example uses a pen injector which aspirates the liquid drug from the system and in turn delivers the drug subcutaneously.
The methods for delivering a powdered drug such as a lyophilized drug include the steps of pressurizing a diluent solution in a diluent vial. The pressurizing systems may include, but are not limited to, a compressed air supply, a chemical gas generator, a collapsible volume supply, a bellow canister, a standard syringe or a cylinder, for example. The methods further include the step of delivering the pressurized diluent solution to the powdered drug vial. The next step in the method includes the reconstitution of the drug to form a liquid drug by mixing the powdered drug with the diluent solution. The methods further include the steps of providing the liquid drug to an injector system or transferring the liquid drug to detachable delivery devices. The following step includes the injection of the liquid drug into the tissue of the patient or user. The methods further include the steps of moving the injection needle from a delivery or injection position to a retracted or storage position once delivery is complete. It should be noted that, depending on the application or delivery of different medicaments, the features of the drug delivery systems may vary. For example, the pressurization level can vary depending upon the viscosity level of the medicament, and the needle type or length can vary depending upon subcutaneous injection or intermuscular injection. For example, for subcutaneous injections, the needle length ranges from 5 to 12 mm while the needle length may vary up to about 3 cm for intermuscular injections.
The methods for delivering a liquid medicament to a patient include the steps of pressurizing the liquid drug solution in the vial with a pressurizing system. The subsequent steps are similar to the steps described with respect to the methods for delivering a powdered medicament.
A preferred embodiment of the present invention features an injector system having an angled or u-shaped needle. Another preferred embodiment of the present invention features an injector system having a straight needle. Yet another preferred embodiment of the present invention employs a transfer system for transferring the drug to delivery devices such as, for example, a standard syringe with a needle or a needleless pen injector. The devices receive the liquid drug from a container, such as a vial containing the liquid drug. The delivery devices subsequently deliver the medication to the user""s tissue as described herein.
Another preferred embodiment of the present invention features a combination system having the ability to reconstitute drug into solution and subsequently inject it into a user. In accordance with this embodiment the reconstituted drug delivery system has a housing having a first opening or port that receives a first container that contains a solid substance, such as a powdered lyophilized drug, for injection. It should be noted that the container is a rigid container, such as, for example, a vial or a cartridge containing the powdered drug. The housing can also include a second opening or port that receives a second container that contains a fluid to be mixed with material in the first container, to form an injectable fluid. The drug delivery system may include a manifold having a first channel that provides fluid communication between the first and second containers. The manifold further includes a second channel between the first container and a delivery or transfer device. The manifold can also include a communication channel to a pressurization system which provides the driving pressure to deliver the liquid drug. In a preferred embodiment, the penetrating member is a needle, in fluid communication with the first container after the needle moves between a storage position in the housing to an injection position extending outside the housing and into the user.
A preferred embodiment of the invention provides for concealment of the injection needle within the main housing of the drug delivery device except during the injection of the drug to the user. This embodiment can include a needle retraction device for withdrawing the needle into the housing after injection to minimize the risk of exposure to a contaminated needle.
In accordance with other aspects of the present invention, the length of the delivery path from the container with the injectable fluid to the injection needle is reduced to minimize loss of residual amount of liquid drug. According to another aspect of the invention, the injection needle first pierces the skin of the person being injected and is concurrently placed in fluid communication with the first container that contains the injectable fluid. According to yet another aspect of the invention, the container that contains the injectable fluid is substantially visible during reconstitution and injection such that the user can visually observe the process. A compressed fluid, such as a gas in the container with the injectable fluid, is used to force the injectable liquid through the injection needle and into the tissue being injected. In an alternative embodiment, the device has a single port with a compression element such that a container with a liquid medication, such as a previously reconstituted material, can be inserted into the housing and simultaneously pressurized to the needed pressure to deliver the correct dose over a predetermined time period.
In a preferred embodiment of the system, the device is used with the injectable fluid container being vertically oriented during injection. To reduce the risk of injecting any gas into the injection site, a gas impermeable membrane such as a hydrophilic membrane is disposed in the fluid path, which in a wetted state minimizes or preferably prevents gas flow while allowing liquid to flow through the membrane. The rigid containers need to be in a vertical orientation during reconstitution for appropriate pressurization. In an embodiment including a cartridge having diluent and air, a vertical orientation is not required for reconstitution. According to a further aspect of the present invention, the axis of the injection needle is perpendicular to the longitudinal axis of the container with the injectable fluid. In a preferred embodiment, the containers containing a powdered or lyophilized drug and diluent are inserted in the housing in the same direction along parallel axes. In another embodiment, the containers are inserted along a common axis or parallel axes in the opposite direction. The system can have housing apertures, ports, or openings that have a size compatible with standard vial and cartridge sizes such that existing vials and/or cartridges can be used. The container contents do not have to be mixed until immediately prior to injection. Because the contents of the containers are only in contact with other sterile parts, sterility prior to and during the reconstitution process is maintained.
According to another aspect of the present invention a further improvement to reduce and preferably prevent the risk of injecting gas into the injection site, includes the use of a drug which is gas impermeable once wetted. Further, since the gas impermeable membrane can sustain pressure, the delivery time for the liquid drugs is shortened as a higher driving force is generated using pressurization systems. By disposing such a membrane such as a hydrophilic membrane in the drug delivery path that is gas impermeable in a wetted state, gas needed to control injection pressure and duration can be added in the system as the membrane checks the delivery of gas to the user. The container containing the fluid can be a changeable volume container which contains a controllable volume of a gas, for example, air. This controllable volume of air and/or fluid are forced into the drug container, resulting in a drug under pressure to deliver the correct dose over a selected time period. According to a further aspect of the invention, the device includes a manifold system to minimize the drug delivery path and simplify assembly costs, and increase system reliability. The simplicity and flexibility of the manifold system facilitates the use of standard prefilled cartridges and syringes. In a preferred embodiment, the manifold is a two-piece polycarbonate molding in which the two molded elements are ultrasonically welded together. The gas impermeable membrane is attached or welded to one piece of the polycarbonate molding.
According to another aspect of the present invention, a further improvement to deliver an accurate predicted volume of a drug includes adjustable height penetrating members, such as, for example, outlet spikes. In the alternative, delivery of an accurate predicted volume, for example 50% or 80% etc., can be gauged from the residual drug volume or the use of detachable delivery devices, for example, a standard syringe or a pen-type pump injector.
According to another aspect of the present invention, a further improvement to the drug delivery systems includes interlocks and indicators which ensure the safe and accurate delivery of the drugs. The interlocks include, but are not limited to latches which provide for a desired sequence of operation such as pressurization of containers to follow the step of insertion of the containers, or prevention of displacement of the needle to an injection position after a first injection use. The indicators include a vertical orientation indicator and end of delivery indicators.
According to another aspect of the present invention, the housing of the drug delivery device is shaped and designed to function appropriately to enable single handed operation. For example, the bottom surface of the housing is flat in shape to allow table top placement to accommodate single handed operation by the user. Further, the device is sized to enable the insertion of vials and subsequent activation of the device using one hand.
In a preferred embodiment, the system housing is lightweight and compact, having a weight of less than 30 grams and a volume of less than 100 cm3. This provides a portable disposable device that can be discarded or recycled after a single use and that is readily transported by the user. In addition, the present invention is self-contained and maintains sterility throughout the reconstitution and injection of a fluid such as a lyophilized drug. It should be noted, the weight and volume of the system housing can vary depending upon the different embodiments and the volume of drug being delivered to a user.